= 1 b 21 [ b 11 b 12 b 13 b 21 b 22 b 23 b 31 b 32 b 33 ] [ R G B ] = 1 0.17697 [ 0.49 0.31 0.20 0.17697 0.81240 0.01063 0.00 0.01 0.99 ] [ R G B ] {\displaystyle
Oxon, UK, 2001, ISBN 0-85199-318-4. 1-146, cited pages: 139 and 142. Burch, JohnB. (1962). How to know the Eastern Land Snails. Wm. C. Brown Co.: Dubuque